This invention relates to an arrangement for diagonally shearing the end of a tube according.
U.S. Pat. No. 1,230,319 shows method for miter-cutting a tube. The miter-cutting shears for tubes known from the mentioned patent is intended for circular tubes or oval tubes where the clamping jaws are recessed corresponding to the shape of the tube and corresponding to the miter square. The tube is surrounded over its whole circumference, in which case one front side of the pair of clamping jaws determines the cutting plane in which both front sides must be precisely aligned with one another and in which the movable shearing blade is also guided. When a miter cut is applied, tube sections are used that are cut to length and these are clamped into the clamping device of the cutting means in such a way that the corner to be cut off projects over the cutting plane. The movable cutting tool then moves from the direction of the profile interior into the projecting corner and shears it off against the stationary cutting blade. A disadvantage in this miter-cutting shear arrangement is that the plane of separation of the clamping jaws that are guided with respect to one another by means of a pair of bolts, corresponding to the desired miter square, is in a sloped position with respect to the closing and clamping direction of the clamping jaws. The direction of the movement of the shearing blade is also sloped with respect to the mentioned plane of separation. The unavoidable play in the guiding of the clamping jaws and the clamping force during the clamping of the tube to be beveled, results in a mismatch of the shearing edges at the clamping jaws that may cause an unclean shearing cut or breakage of the shearing edges. In any case, this causes an imprecise guiding of the movable shearing blade with respect to the stationary shearing blade. Another disadvantage is that the known miter-cutting shears for tubes cannot be used universally, i.e., for different shapes of tubes or different miter squares.
These are probably the reasons why the miter-cutting shears known from the text have not proven themselves and have not been widely used in practice. In contrast, as far as the applicant knows, miter cuts on tubes were made only by machining by means of sawing or abrasive cutting. This method is time-consuming, noisy and dirty because of the resulting grinding dust or sawdust. It is only known to the applicant to carry out axially vertical shearing cuts perpendicular to the axis of the tubes in order to cut them to length in a way which takes place rapidly, quietly and without dust. However, when using the known devices for this purpose, a miter cut is not possible.
It is the object of the invention to design a miter-cutting shear device which provides clean miter cuts and a perfect guiding of the movable shearing blade with respect to the stationary shearing blade.
According to the invention, this object is achieved by providing a clamping device with a clamping force direction, transverse to the moving direction of the shearing process. Therefore, as a result, there is no mismatch of the stationary shearing edges caused by play and clamping force. In contrast, the miter square and the clamping force have no effect on the quality of the mutual guiding of the shearing edges with respect to one another, thereby ensuring a clean shearing cut.